We hypothesized that because politically conservative ideology legitimizes the status quo—including heteronormative institutions and arrangements—it should be negatively associated with in-group identification, opposition to homophobia, and support for LGBTQ+ rights among sexual minorities. These hypotheses, which were derived from system justification theory, were assessed in large US samples of sexual minority respondents. In Study 1 (N = 4,530) and Study 2 (N = 1,107), we observed that more conservative sexual minorities expressed weaker sexual identification, and, relatedly, less support for same-sex marriage and adoption and other rights and privileges, as well as less participation in collective action in favor of LGBTQ+ rights. In Study 3 (N = 446), heterosexist system justification was associated with decreased sexual identification and support for LGBTQ+ rights. In all studies, identity and ideology accounted for unique variance in support for vs. opposition to LGBTQ+ rights. Implications for the politics of sexual identity and collective action among disadvantaged groups are discussed.